Is it really calling another instance of yourself, without some kind of cloning? Like usually that kind of thing is used in time travel stories, where you call a previous version of the character forward, but then there are two of them there. Whereas in this case, a higher existence fell down to a lower level; it's not that she's a weaker Zashiki because of the Fallen title, it's that she's a Zashiki because she fell down from something else, and the new ability is calling back her previous power.
It's somewhat right and wrong (it's hard to explain).
The reason Renka is a weaker Zashiki, is because there are other Zashiki's which are stronger than her
(keep in mind, each cards have multiple copies out there, but each one is different in someway, basically Zashiki is considered as a Race/Species), not because they are actually powerful, but rather because Renka is a "Fallen Existence", so she is weaker than her counterparts. So, as far the Skill goes, she is considered as a Fallen Zashiki.
As for Renka's higher form, that's only accessible to those who has the "Fallen Existence" skill, which transforms into the "Spiritual Recursion" skill when certain condition are met (as you can read in the card skill list, Renka had lost the "Fallen Existence" skill, and it's replaced by "Spiritual Recursion" skill).
In the case of "Spiritual Recursion", the cards are temporarily Ranking Up to access their higher ranked forms. This is sort-off like a time-manipulation, as they are calling their future forms to appear temporarily on their current selves. The reason why i say future forms, is because they are not losing their own self, aka., Renka didn't lose her self-identity.
